diff --git a/src/x86/Set_test.go b/src/x86/Set_test.go
index 10df804..6f7d2a4 100644
--- a/src/x86/Set_test.go
+++ b/src/x86/Set_test.go
@@ -34,6 +34,9 @@ func TestSet(t *testing.T) {
 		{x86.R1, 9, []byte{0x0F, 0x92, 0xC1}},
 		{x86.R0, 10, []byte{0x0F, 0x96, 0xC0}},
 		{x86.R1, 10, []byte{0x0F, 0x96, 0xC1}},
+		{x86.R5, 1, []byte{0x40, 0x0F, 0x94, 0xC5}},
+		{x86.R6, 1, []byte{0x40, 0x0F, 0x94, 0xC6}},
+		{x86.R7, 1, []byte{0x40, 0x0F, 0x94, 0xC7}},
 		{x86.R8, 1, []byte{0x41, 0x0F, 0x94, 0xC0}},
 		{x86.R9, 1, []byte{0x41, 0x0F, 0x94, 0xC1}},
 	}
diff --git a/src/x86/encode.go b/src/x86/encode.go
index 4563d69..ac99129 100644
--- a/src/x86/encode.go
+++ b/src/x86/encode.go
@@ -27,7 +27,7 @@ func encode(code []byte, mod AddressMode, reg cpu.Register, rm cpu.Register, len
 		code = append(code, byte(opCode>>24))
 	}
 
-	if w != 0 || r != 0 || b != 0 || (length == 1 && reg >= SP && reg <= R7) {
+	if w != 0 || r != 0 || b != 0 || length == 1 && (reg >= SP && reg <= R7 || mod == AddressDirect && rm >= R5 && rm <= R7) {
 		code = append(code, REX(w, r, 0, b))
 	}
 
diff --git a/tests/bool-2.q b/tests/bool-2.q
new file mode 100644
index 0000000..a61e1ca
--- /dev/null
+++ b/tests/bool-2.q
@@ -0,0 +1,18 @@
+main() {
+	a := 1
+	b := 2
+	c := a < b
+	d := b < a
+	e := a > 0
+	checkFalse(d)
+	checkTrue(c)
+	checkTrue(e)
+}
+
+checkFalse(v bool) {
+	assert !v
+}
+
+checkTrue(v bool) {
+	assert v
+}
\ No newline at end of file
diff --git a/tests/tests_test.go b/tests/tests_test.go
index 9fa9e9f..cb20479 100644
--- a/tests/tests_test.go
+++ b/tests/tests_test.go
@@ -49,6 +49,7 @@ var tests = []run{
 	{"branch-or", nil, "", "", 0},
 	{"branch-both", nil, "", "", 0},
 	{"bool", nil, "", "false\ntrue\nfalse\ntrue\nfalse\ntrue\ntrue\ntrue\n", 0},
+	{"bool-2", nil, "", "", 0},
 	{"jump-near", nil, "", "", 0},
 	{"reorder-blocks", nil, "", "CDFH\n", 0},
 	{"switch", nil, "", "", 0},